Stabilizing means for weighing scales



Dec. 6, 1949 s, w| 2,490,723

STABILIZING MEANS FOR WEIGHING SCALES Filed June 25, 1947 I 2 Sheets-Sheet 1 mmvrox. E g- I Lawrence 5. l'Vi/fiams M4 ZZORNEYS Dec. 6, 1949 L. s. WILLIAMS 2,490,723

STABILIZING MEANS FOR WEIGHING SCALES Filed June 25, 1947 2 Sheets-Sheet 2 A ZawF mm w 5 iv!!! 1 e n C n Patented Dec. 6, I I 2,

UNITED STATES PATENT OFFICE STABILIZIN G MEANS FOR WEIGHING SCALES Lawrence S. Williams, Toledo, hlo, assignor to Toledo Scale Company, Toledo, Ohio, at corporation of New Jersey Application June 25,1947, Serial No. 756,919

' 6 claims. (01. 308-2) 1 2 This invention relates to weighing scales, and in the second part, and a link engaging said memin particular to means for preventing derangebersfor preventing separation of said parts. ment of the weighing mechanism when heavy he mp oved s abi n ea p es bloads are applied near an edge of a load receiver. stantially frictionless resistance against separa- Weighing scales. particularly those intended for 5 on o t Par s O the Weighing scale ca use in retail food stores, are commonly constructed the knife e in e fi st me ber ay rock with a single A-shaped lever that serves to supagainst the end of the link and because no stress port the load receiver and transmit load forces is s t up n e l ot r th n the orc actu ly I to an automatic load counterbalancing mechqu r d t pr v t th h ar fr m leavi th anism. The load receiver is maintained in upknife g right perative position by a check link As long The improved construction also allows the knife as the resultant of the load forces acts near the e vof the stabilizing means to b accurately center of the load receiver, no stability problems aligned With the oad ca y fe edge of the are introduced. If, however, the load is applied l T s f r s m r n in t t it pernear the edge of the load receiver there is a tendmits the stabilizing m ns o be j s d wi h ency to rock the load receiver and lift one of its minimum Clearance and yet maintain that clearbearings from the cooperating knife edge pivot, of ance throughout the normal operation of the scale.

the lever. Unless this lifting of the bearing from The Preferred m the invention s usthe pivot is prevented the load receiver will tip t d in he c o pa ying d awings. to such an extent that the scale becomes inopera- In the drawings! tive. Various devices have been proposed to pre- Figure I is .a side elevation with parts broken vent such derangement of the weighing mechaw of a weighing scale d ng the improved nism but they have either been too costly or have Stabilizing meansintroduced too much friction into the weighing Figure II is a fragmentary p V w s owing mechanism, the space relationship between the load receiver The principal object of this invention is to proand the lever of the s vide a simple, economical mechanism for stabiliz- Figure III is a fragmentary p an iew as seen ing a weighing scale against the possibility of de- IIOm the line o Figure rangement resulting from loads applied near the Figure IV is a vertical section taken stanedge of the load re iv tially along the line IV-IV of Figure III, to show Another object of the invention is to provide a fulcrum pivot of 1ihe stabilizing means, the parts of which do not carry Figure V is f Vertical section taken along t load except when required to prevent the lifting line of Flgul'e III to Show a load pivot 0011- of a bearing from the cooperating pivot. nection- A still further object is to provide a stabiliz- Figure VI is a fragmentary side elevation of ing means that is simple to adjust and which is h lead P o as se from the llne VIVI' of not liable to get out of adjustment during use. i Flgure These and other objects and advantages are ap- Figure VII s an e a fragmentary section I parent from the following description in which taken along the line VII-VII of Figure reference is made to the accompanying drawings. 40 Figure I is a detail view showing the 0 D- The invention consists in stabilizing mechanism oration between e various members of he t for a weighing scale pivotal connection, comprisblnzmg n e ing, mean i a first member for defining a pivot- Figure 1X is a detail view of the connection being axi capable f receiving force from various tween the stabilizing link and one of the members directions, and mechanism in a second member With Which t cooperatescooperating with said means for transmitting These sp c fic figures a d e co pa y force to the said means regardless of the direction descripti are in nd d e e y to illustrate the of the force. invention but not to impose limitations on the In the preferred form the stabilizing means is claimsused with a pivotal connection in which a knife A p c W g scale in Which h improved edge pivot in a first part cooperates with a.V-bearstabilizing, means may be empl yed s a load ing in a second part and com rises a first member receiver l secured to a spider 2 which is p v ll mounted in the first part and having a knife edge supported from a lever 3. The lever 3, in plan, substantially aligned with the pivot and directed is substantially triangular in form and is fuloppositely to the pivot, a second member carried crumed at the front corners of a base 4 and has through a rack to a pinion l tthat is mounted on the shaft of the indicia-bearing chart 8. The load counterbalancing mechanism rotates the chart 8 through angles that areproportional to the load forces transmitted from the load receiver I through the lever 3 to the counterbalancing mechanism.

The spider 2 is prevented from rocking. about its pivotal connection to-the lever 3 by a check link l2 that is pi-votally connected throughopposed knife edges and pivots 93 to the upper end of a post l4 extending'upwardly from the central portion of the spider 2. The otherend of the check link I2 is pivotally connected through knife edge pivots and bearings l 5 to a post is that is adjustably mounted from a pedestal i'i erected from the base i. The adjustment of the mounting of the post 16 from the pedestal l 1' permits the line of action of the-check link 12 to be adjusted until it is precisely parallel to the pivot line of the lever 3.

ward force, the bearings 21 will be maintained in operative position on the knife edge pivots 28. If, however, the load is concentrated toward one side or the other of the load receiver so that the resultant of the load forces falls between one of the pivots 28 and the adjacent edge of the load receiver l the opposite load pivot. is completely relieved of load and that arm of the spider tends to lift until its upward motion is limited by the cap 29. The area of the resulting contact between the cap 29 and the pivot 28 and the distance of that contact from the knife edge of the pivot 28 introduces a serious amount of friction as well as producingactual change in load indication.

To prevent this separation between the knife edge pivot 28 and the bearing 21 resting thereon, a stabilizing means connecting the pivotally connected parts of the scale is employed. This stabilizing means consists of-a first member 32 that ismounted in the first part of the weighing scale mechanism-the lever 3.. The first member 32 I comprises a cylindrical shank. portion 33 that is, fitted. through a hole in the lever 3 and a head portion 34 that provides av pair of pivot edges.

*Thefirst member is made from. square stockby Referring to Figures II, III and IV, the lever 3 is provided with tench-shaped fulcrum pivots [8 that extend laterally from the wide end of the lever 3. The fulcrum pivots i8 are pivotally sup ported in v-bearings I!) that are mounted in the corners of the base 4. The V bearings 19 are made self-aligning by forming a portion of their surface to the contour of a sphere the center of which lies in the center of the: V-groove in the bearing. The speherical portion of the V-bearing [9 rests in the conical portion of a drilled and countersunk hole 20 cut in the base 4. A cylindrical shank 2| formed integrally with the vbearing [9 is loosely engaged in. the drilled portion of the hole 28 to limit the freedom of movement of the V-bearing l9. A cap 22 lssecured to the surface of the. base 4 adjacent .thebearing l9 and shields the knife edge l8 and. bearing l9 from any dust or dirt that may find its way into the interior of the scale housing. A hardened screw 23 that is threaded through a portionof 29 secured to the end of the arm has a.por-.

tlon that extends downwardly and under the load pivot 28. A screw 30 secured by a lock nut'3l is threaded through the ca 29' in axial alignment with the knife edge of the pivot 28 and serves as a thrust bearing to maintain the bearing 21 in position along the knife edge of the pivot 28.

Referring to Figure II, if loads are placed near the center of the load receiver [the force is distributed or divided between-the load pivots 28 and since each of the pivots is subjected to a downportion 34.

counterbore 36 of sufiicient diameter and depth to turning the greater portion of its length to form the cylindrical shank portion 33 and then cutting off two corners of the headportion to reduce its width to correspond tothe diameter of the shank portion. The two remaining corners of the originally square stock provide the pivot edges for the member. A washer 35 is slipped over the shank portion 33 and is staked against the head The lever 3 is provided with a completely receive the .washer 35 and the head portion 34 when it is desired to retract these members from their normal position adjacent the 3 end of the knife edge of the. pivot 28.

The upper surface of the end of the spider arm 25 is provided with a V groove 3.? that partially receives a short cylindrical rod constituting a second member 38 of the stabilizing-mechanism. A short bar 39 secured by a pair of screws 40 serves to clamp the second member in position.

Referringto Figures VIII and IX, one end of the second. member 38 is provided with a groove 4f. the. root circle of which groove is eccentric to .rthe axis of the cylindrical portion of the member 38. A formed link 42 is suspended from the groove 4! with its lower end engaging one of the square :corners of the head 34 of the first member 32. The relative cooperation and positioning .of the first and second members and the link is clearly shown in Figures VII and VIII. In these figures it will be noticed'that one of the square edges that provides the pivoting edge for the head 34 of the first member is positioned in op- :.position to, in alignment with and adjacent the end of the knife edge portion of the pivot 28. The eccentric groove portion of the second member 38 is positioned vertically above the pivctedge of the head 34. The link 42 is provided with V- bearing surfaces in each of its ends so that it is symmetrical and may be assembled with either end uppermost. The link is further formed by pressing the V-bearing portions out of the plane of the remainder of the link so that the equivalent of thrust points are provided for cooperation with the washer 35 and the end of the pivot 2.8.

Either of the fulcrum pivots I8 is also liable. to be raised out of its cooperating -V-bearing L9 Y in the event that a sufiloiently heavy load isapplied near the edge of the load receiver I. This lifting is prevented by a similar stabilizing mechanism comprising a first member 43 that is mounted in the lever 3 and which has at least one pivot edge 44 that is positioned in substantial alignment with and adjacent the end of the knife edge of the fulcrum pivot [8. A link 45 suspended from the pivot edge M engages an eccentric groove 46 in a second member 41 that is clamped in a V-groove 48 cut in the base t. A bar 49 secured by a pair of screws 5!! serves to clamp the cylindrical second member 41 in position.

This stabilizing mechanism is very easy to install and adjust inasmuch as the pivot edge of the head 34 may, by visual inspection, be accurately aligned with the load or fulcrum pivot 23 or it. In order that the first memberthe member having the pivot edgemay be installed after the fulcrum and load pivots are ground, a notch 5! is cut in the washer 35 to allow the washer to pass the knife edge of the pivot. It is also possible to install the first member in the lever before the pivots are set, the member being withdrawn into the counterbore during the final grinding of the knife edge pivot. The eccentricity of the groove in the second member permits the clearance or slack between the link and the pivot edge in the first member to be adjusted by merely rotating the second member. Since the amount of adjustment required is slight and the amount of eccentricity is comparatively large, the second member 38 or 4'! need not be rotated through a very large angle and, therefore. the ii-grooves may be offset from a vertical line through the V-bearings by an amount substantially equal to the eccentricity of the groove so that the links hang vertically.

The combination of this stabilizing mechanism with the pivot and bearing may be considered as a structure having a turning axis, the knife edge of the pivot and the aligned pivot edge of the first member, and means for engaging the upwardly or downwardly directed portion of the structure providing the turning axis according to the direction of the force applied to the pivotally connected parts of the scale. Since the turning axis is positively defined and is substantially the same whether the force be directed upwardly or downwardly a load near the edge of the load receiver that reverses the direction of the force transmitted through the pivotal connection cannot affect the accuracy of the load indication. Whether the link of the stabilizing mechanism is carrying load or not the only relative motion between the parts of the complete pivotal structure is the rocking motion of the pivot edges against the cooperating V-bearings whether the V-bearing in the link or the V-groove bearing cooperating with the knife edge of the pivots 2B or 68 be carrying the load. For this reason it is not necessary to provide a knife edge in the second member, the member having the eccentric groove.

In the event that the lever exhibits a change in ratio when the load is applied sufficiently near the edge of the load receiver to cause the opposite bearing to lift against the stabilizing mechanism the first member may be rotated slightly so that its pivot edge is no longer in vertical alignment with the knife edge of the load pivot, the misalignment being in such a direction that the forces transmitted through the link tend to correct the observed error in ratio.

Various modifications may be made in the details of construction without departing from the spirit and scope of the invention.

Having described the invention, I claim:

1. Stabilizing mechanism for a weighing scale in which a knife edge pivot in a first part cooperates with a V-bearing in a second part for pivotally connecting the parts, in combination, a first member mounted in the first part and having a knife edge substantially aligned with the pivoting axis defined by the pivot and directed oppositely to the pivot, a second member carried in the second part, and a link engaging said members for preventing separation of said parts.

2. Stabilizin mechanism for a weighing scale in which a knife edge pivot in a first part cooperates with a V-bearing in a second part for pivotally connecting the parts, in combination, a first member mounted in the first part and having a knife edge portion that is oppositely directed to the knife edge pivot and that is adjacent to the pivot and is substantially aligned therewith, a second member that has an eccentric portion and that is attached to the second part, and a link engaging the eccentric portion of the second member and the knife edge portion of the first member for preventing separation of said parts.

3. Stabilizing mechanism for a weighing scale in which a knife edge pivot in a first part cooperates with a V-bearing in a second part for pivotally connecting the parts, in combination, a first member that has a generally cylindrical shank that is received in a hole in the first part, the member having a knife edge that is directed oppositely to the pivot and that is substantially aligned with and is adjacent to the pivot, a second member adjustably mounted in the second part and a link engaging the second member and the knife edge of the first member for preventing separation of said parts.

4. Stabilizing mechanism for a weighing scale in which a knife edge pivot in a first part cooperates with a V-bearing in a second part for pivotally connecting the parts, in combination, a first member that has a generally cylindrical shank that is received in a hole in the first part, a non-circular flange on the end of the member having peripheral portions that meet to form at least one pivot edge, said first part having a counterbore at the end of the hole to receive the when flange it is not in use, the hole in said first part being located so that the pivot edge of the flange is in line with the knife edge pivot, a second member that is mounted on the second of said parts, and a link engaging the second member and the pivot edge of the first member for preventing separation of the parts.

5. Stabilizing mechanism for a weighing scale in which a knife edge pivot in a first part cooperates with a V-bearing in a second part for pivotally connecting the parts, in combination, a first member that has a generally cylindrical shank that is received in a hole in the first part, a pivot edge formed on the member and positionable in adjacent alignment with the knife edge pivot, a second member mounted in the second part, a link engaging the second member and the pivot edge of the first member, and a thrust surface on the first member for axially positioning the link.

6. Stabilizing mechanism for a weighing scale in which a knife edge pivot in a first part cooperates with a V-bearing in a second part for pivotally connecting the parts, in combination, a

aneurysm 7* as member mountediin the .first part; said member r presenting a pivotxedge that is oppositely di-e REEERENGES CITED" rected, adjacentito and substantiall aligned with The:followingsreferencesa are Off'I'BCOI'ddHZthB the knifeedge' pivot, 21. v groove in the second file 0f this patentt' part from which the'seatior the V-bearing is 5. v located, a generally cylindrical member. mounted STATES" PATENT-S in the V-groeve; and alinkengagingxthe cylin- Number Name Dat drical member and the pivot" edge of the first 1,685,780" Hem Oct. 2;; 1928 member for preventing separation of the parts. 1,751,980 Dean: Mar; 25, 1938:-

LAWRENCE S. 10= 212411349 Hem-z May 6,1941? 

